5 urgent biology questions?

Question

1) What is the purpose of the rough ER (in the cell)?

2) What is the purpose of the smooth ER (in the cell)?

3) What is cellular respiration?

4) One of the cells main function is to maitain homestasis. what does this mean? five reasons why this is true???

5) What are diffusion and osmosis? how do they relate to the function of a cell membrane?

answers to ANY of these questions is appreciated!

Answer 1

RER -- http://www.britannica.com/eb/article-37394/cell
SER -- http://www.britannica.com/eb/article-37393/cell

Check out www.britannica.com to search for concise answers to your other questions. Remember to cite your sources (@ the bottom of each article, Britannica shows the citation info)

Answer 2

1)Ribosomes attached to rough ER synthesize proteins which are transported within the Er for processing and sorting. Sometimes enzymes attach carbohydrates to form glycoproteins. Sometimes enzymes attach the proteins to phospholipids which are also synthesized by the rough ER.

2)Smooth Er extends from the rough ER as a network of tubules. Synthesis of fatty acids and steroids occurs here.
In liver cells, smooth ER produces enzymes that detoxify drugs and alcohol.

3)A series of chemical reactions the produce most of the cells ATP.

4)Homeostasis is internal equilibrium despite changing external conditions. It is acheived primarily by negative feedback systems.
I don't understand what you mean by why is this true.

5)Diffusion is a passive movement of molecules from an area of high density to an area of lower density until equilibrium is reached.

Osmosis is the net movement of water through a selectively permiable membrane (such as a cell wall)

Answer 3

Cillia and flagella are tiny hair-like structures used by many single celled organisms as a form of locomotion. Sperm cells also move in this fashion. Diffusion and osmossis are passive reactions which require no energy. Active transport is the movement of ions and molecules in which energy is used. Mitosis takes place mostly in the nucleus when the chromosomes replicate themselves. From here, it spreads through the remainder of the cell, which itself divides into two identical cells. Chromosomes are densly packed sections of DNA in association with special protiens. They are found in the nucleus of the cell. Prokaryotic cells have a single membrane which separates the inside of the cell from the outside. Eukaryotic cells have many additional membranes inside the cell. The chromosomes are enclosed in a nucleur membrane. Bacteria are prokaryotic cells. All other forms of life on earth are composed of eukaryotic cells.

Answer 4

1) Rough endoplasmic reticulum has ribosomes studding the outer membrane. The ribosomes are the sites for protein synthesis in the cell.

2) Smooth endoplasmic reticulum has a role in cholesterol synthesis, fat metabolism, and detoxification of drugs.

3) Cellular respiration, or oxidation, involves the use of oxygen to release energy stored in nutrient molecules such as glucose. This chemical reaction occurs within the cells. Much of the energy released is in the form of heat to maintain body temperature. Some of it, however, is used directly by the cells for such work as contraction of muscle cells. It is also used to carry on other vital processes. Food, when oxidized, gives off waste products include carbon dioxide and water vapor. These waste products are carried away through the process of internal respiration.

4) The maintenance of internal environmental conditions is known as homeostasis. Human survival depends on maintenance or restoration homeostasis. For living cells to function optimally, their biochemical reactions must maintain homeostasis. A state of homeostasis is required for the body to function at an optimum level of health.

5) Diffusion is a physical process whereby molecules of gases, liquids, or solid particles spread or scatter themselves evenly through a medium. Diffusion plays a vital role in permitting molecules to enter and leave a cell in maintenance of homeostasis.

Osmosis is the diffusion of water or any other solvent molecule through a selective permeable membrane. Osmosis is the movement of water molecules across a semipermeable membrane from an area of higher concentration of a solution to an area of lesser concentration of a solution to maintain homeostasis.